Conventionally, automobiles use electrical connection boxes, such as relay boxes and fuse boxes. An electrical connection box houses a branching connector, on which a plurality of relays, fuses, and the like are mounted and to which wire harnesses, coming in from outside, are connected. The branching connector houses a circuit unit from which a plurality of connector terminals project, both above and below the outer surface of the circuit unit. These connector terminals also project through the upper case of the branching connector to connect fuses, relays and the like and into the lower case of the branching connector. The circuit unit is formed by stacking a plurality of circuit boards, one on top of the other. Circuits are formed from a plurality of bus bars, which make up the circuit board, and the connector terminals extend from the bus bars.
Generally, the inner surface of the branching connector abuts the upper surface of the circuit unit and the connector terminals project through the upper case of the branching connector. The individual connector terminals are positioned in and can form, for example, relay cavities, fuse cavities, or connector mounting openings. These fuse cavities, relay cavities and connector mounting openings are generally part of the upper case into which the fuses and connectors are positioned.
When assembling the branching connector, the circuit unit is positioned inside an upper case and a lower case, and the upper and lower cases are connected and fixed to each other by pairs of elastic engagement pieces disposed on each of the cases. If the branching connector is assembled so that the upper surface and the lower surface of the circuit unit do not tightly abut the inner surfaces of the upper case and the lower case, the connector terminals will not project a predetermined length through the case. As a result, the relays, fuses, and the like will not be reliably connected to the connector terminals.
When assembling the branching connector, a tool is used to apply a predetermined load to cause the elastic engagement pieces on the cases to connect. Since it is not possible to confirm whether the upper case, the lower case, and the circuit unit are properly aligned before connecting the two cases, it must be assumed that the circuit unit and the upper and lower cases are aligned when the elastic engagement pieces are aligned and the tool connects the upper and lower cases. Furthermore, since the elastic engagement pieces are disposed on the sides of the cases, it is not possible to confirm whether the central portions of the circuit unit are properly positioned in the casing, even when the elastic engagement pieces are engaged. There is thus a need to provide a branching connector wherein the circuit unit and the upper and lower cases can be properly assembled in a reliable manner.